Method of winding electrical capacitors



Feb. 25, 1947.. E A mRDBE G 2,416,540 I METHOD OF WINDING ELECTRICAL CAPACITORS Filed July 20, 1945 5 Sheets-Sheet 1 Feb; 25, 1947.

Filed July 20 1945 5 Sheets-Sheet 2 Feb. 25, 1947. E.- A. NORDBERG 2,416,540

METHOD OF WINDING ELECTRICAL CAPACITORS Filed July 20, 1943 5 Sheets-Sheet 5 z'mm/z awier wi was Feb. 25, 1947. I 1 E. A. NORDBERG METHOD OF WINDING ELECTRICAL CAPACITORS Filed July 26, 1945 5 Sheets-Sheet 4 rwenh? Feb. 25, 1947.

E. A. NORDBERG METHOD OF WINDING ELECTRICAL CAPACITORS Filed July 20, 1945 5 Sheets-Sheet 5 Patented Feb. 25. 1947 METHOD OF WINDING ELECTRICAL CAPACITORS Ernst A. Nordberg, Norwood, Mass, assignor, byv to Tobe Deutschmann,

mesne assignments,

Canton, Mass.

- Application July- 20. 1943, Serial No. 195,466

2 Claims. (01. 242- 56) This invention pertainsto the manufacture of electrical capacitors especially to capacitors which comprisecoils of metal foil separated by a thin layer or layers of a dielectric material, and relates more particularly to a novel method of winding such capacitors.

Capacitors of this type are commonly made by drawing off two lengths of thin metal foil ribbon from supply rolls while at the same time drawing off one or more'lengths'of thin paper or other flexible dielectric material from similar supply rolls and winding the foil and .paper simultaneously on a mandrel in such a way that the convolutions of metal foil are always separated by at least one layer of paper. In thus winding the foil and paper it is necessary that the final convolution of paper overlap the ends of the metal foil in order to provide'a complete seal for the metal and also that the two strips of metal foil terminate at points spaced circume ferentially of the coil so as to insure against short circuiting. It is preferable to employ a plurality of thin paper strips rather than a single thicker strip since the thin paper is more flexible and makes a firmer and more compact coil than a single thick layer. Furthermore the employment of a plurality of thin layers avoids short circuiting' such as might result from the 'o'c'cur-.

rence of pin holes or other defectslin one layer. Heretofore in winding coils of, this type it has been customary for the operator, after a suiiicient length of foil has been wound, to stop the winding operation temporarily, sever the several strips of material, turn back the ends of the outer paper wrappings so as to expose the metal, cut off the two lengths of'metal foil atthe proper points and then continue thewinding with the projectingend portion of paper alone so'that the paper may properly overlap the metal. This procedure involves a substantial'waste of the metal foil which is a matter of realimportance at the present time when metal foil is so expensive and difficult to obtain. Moreover the described operations involved in the removal of such-portions of the metal foil slow down production very substantially. t y

The principal object oi the present invention is to provide a novel method of winding such capacitors whereby the waste of. metal foil is completely eliminated'and whereby theoperation is facilitated and speeded up. for winding capacitors of either the inductiveor non-induce tive type at high speed and whether they'comi prise one'or'a plurality ofpapenwrappings' A further object or the presentinventlon to pro-.

vide a winding method which facilitates the severance of the metal foil prior to the completion of the winding operation and before the end portions of the foil have been wound about the winding mandrel, and in such a way that the two strips of metal foil terminate at substan: tially diametrically opposite sides of the coil while the paper extends well beyond the metal.

foil to form an effective seal. A further object is to provide a winding method capable of windingver-y thin and delicatefoil together with the thin paper with a'minimum amount of breakage and loss. .Other and further objects, and advantagesoi the invention will be pointed out hereinafter in the following more detailed de-' scription and by reference to the accompanying drawings wherein r Fig. 1 lsa fragmentary diagrammatic right hand side elevation illustratingone form of apparatus embodying the invention;

Fig. 2, is a front elevation of the apparatus Fig. 6 is; a fragmentarydiagrammatic trans verse section'to enlarged. scale through one. of the elements ofthe winding mandrelillustrating the step of associating one strip of metal foil and its accompanying paper wrapping with the mandrel; p v

Fig. 7 is a similar viewshowing the other strip of metal foil associated with the mandrel; V V Fig. 8'is adiagrammatic end elevation showing the relative position of the feed rolls during the actual winding operation; Fig. 9 is a view generally similar toFig.v 7' but" showing the mandrel after it has made the first quarter turn inethe winding operation; I. Figs. '10 and Here views similar'to Fig.-.9'.showing the mandrelas having turned a quarter turn and a half turn respectively beyond the posid lemmas;- 1 rl Fig. 12 is a view-similar to Fig. 8 "showing the they occupy justfeed rolls in V the position which prior to the cutting operation; V Fig. 13 is a diagrammatic side elevation, to larger scale illustrating themeans for moving Y the memlmerv 5.,

the lower feed roll toward and from the upper the completion of the winding-operation.

Referring to the drawings, more especially to Fig. 1, the frame of the. machine is shown as comprising the substantially parallel, horizontal; rigid rails I 2 and 3 which are supported by uprights 4 (but one being shown) designed to be mounted ,upon any suitahle support f or example abfench or the like. Themidd e ail 2 projects o war y b nd the ra Iv an .a d' e a vertically disposed plate 5 ofsubstanti'al thickness and of rigid materialwhich supports much of the jj'ects a rigid, substantially horizontal, transverse bar. ;which supp ai qndar ver ic ll l te o fram m er .1. paral el. to and s e 9m, e plate. .5; Projecting fromthe left-hand side of t eplate (F e- 2 i an th ho i nta b supporting at its outer. end another vertical frame member; or block 9 parallel to but spaced from Moun dio th u per. r l i se i 'o js l shafts HI, Hi and In? which aresecurely held in rigid, horizontalpositionby means of nuts 12 (Fig! 3), Which.unite them ,to therail IL In a similar way the rail'jj sup'ports a lower series of y stub shafts Ll, H and II". Each of these stub shafts carriesvagcollar 13 (Fig; 2) justat the right-handside of thecorresponding rail and on eachof the shafts to the rightof the collar 3 several paper strips are caused to register while is mounted a reel [4 having spaced flanges 14 y and [4 These reels are designed'to hold supply rolls of paper and metal foil-and are removable when empty from; their respective stub shafts o r p ace t. w t u r fil P fi b y a co led sp ing; l5 embraces each stub shaft,- bearing'at its left-hand end against the face of; the reel and at its right hand' end against an abut-- ment collar 16 which isheldin properlyadjusted 7 position onthe shaft byrheansof-aset screw H.

By adjustment of the collars l6; along the shaft the springs, l5 maybe compressed' more or less and thus their frictionalcontact with the reels may be varied. In this way. an adjustable braking effect is'provided to restrain the reels from turning-too freely. 1

"A stub shaft 3- (Fig. 1) projecting from the middle railcarries aguide roll beneath which pass the paper ribbons -P i-and F from the reels ,whichare mounted on thestub shafts l0 and I09.

Another stub-shaft l '9zprojecting. from the rail 2. carries a guiderolli beneathawhichpasses the ribbon ofmetal. foil F' from there'el mountedon the rail 2 further assisting in guiding these. latter strips. :Tl evertic i fixedfparallel, horizontal guide rodsg22, 23, 24

and 25 (Fig. 17) which are smoothly polished and constitute guiding means for the paper and foil. On these rods, and abutting the member 5,

are mounted fixed sleeves 22 23 24 25 respectively. The sleeves 22* and 24' are of equal lengthandtheir outer end facesare designed to engage one edge of the paper strips P and P and P and P respectively. The sleeve 23 is shorter than sleeve 272 and designed to engage one edge of the foil F Sleeve 25* is longer than sleeve and ,is designed to engage one edge of foilLF By this arrangement the'edgesof the the, foilsareoffset, in opposite directions, that is to say,. themarginf of one foil projects beyond one edge of' the paper strip while the opposite margin of the other .foil projects beyond the opposite edge of the paper strip. This arrange- 'ment is designed for use in winding non-inductive coils but if it be desired to wind inductive coils then the sleeves .23? and 2 5 pare replaced by sleeves of equal length and somewhat longer than the sleeves 22 and 242, thereby to space the margins ofthe two foils inwardly from the edges of th paper strips. I

While, smooth.. surfacedi guide rods 2 2, 23, etc., are sufficient under' ,ord inar'y conditions, it' is contemplated that theserods may constitute stub shaftsfor the supportiof guide rolls properlycontoured to align the paper and foil in the manner above described. a:

In a vertical plane forwardly of the guide rod 25 there is arranged the shaft 26 of an upper feed roll. This shaft turns in a fixed tubular bearing 21 projecting'from the left-hand side of the frame member S and in a bearingfin the part 9'. Just to the right, ofpart 9, the shaft carries a pinion 28 which meshes with arack 29'wh0se lower end is pivotally connected. at 30 (Fig. 3) to a long lever 33 whose rear end is mounted upon a stub shaft 34 fixed at its righthand end in the frame member 5,.the forward endtliof theleyer 'con'stituting a handle by means of which the lever may be moved downwardly, thereby to cause the rack 29 torotatethe pinion 2 8 and the feed roll shaft .26. Th'elever 33 has a hub rncrnbe r 3 19! (Fig. 2)l which arms on the shaft 3gi', and a coiled spring '33 (Figs, "2am. '3') ,engages the lever and encircles the. shaftli3 lvv and is so arranged as to tend to raise the lever 33 and thustomove thera clgzfl upwardly. v.

, Miountjed an the shaft26Ytothe right or the pinion ,28 is. a. clutch, spool 2'8! (Ei'g. '2). The pinion 28 has a hub which. cooperates withth'ev left handfside of. the .clutch ispool 28 to'drive thejspoollpositively as the pinion is turned-by the downward movementof .therack 29,. Interposed between the-pinion hub and spool 28. is. any

1 suitable type of one-way drive (no.t shown) such arts,

for, example asapawl or ballclutch, the details of which, need .not, be specifically illustrated as such devices are. of common. knowledge in the t.i t paieiiaaigtatat 'gsai a adpa ates with a retaining device loose onland. coaxial withshaft 26 and held againstrotationhya forked. ,.arm-; 28- e igaging the bar 8. Interposed hetween the spool. and retaining device is a pawl seecti-v l r s cond r guider h r ied. b

orjball clutch of; conventional. type. so designed astofprevent reverse movement of the spool 28? anais aa T26, while 'tl iefrack. ,2'9. being raised..

. The shaft 26 isthus constrained. always 'to mov in thej same. directiomisuch. direction; being that white}.....efe9ev9i L-f -dfih a r n ie l the winding mechanism. By'this'arra'rige'rlihtja rufu'thiew brieyer ann' ss te tes-tiny ams-"ti e,

upper feed rolhthrough a predetermined angle and thus advances an accurately measured length of paper.

-- The shaft 26"has fixed'to it the amalfeed r011 36 which cooperates with the lower feedroll 31;

This lower feed roll (Fig. 16) is mounted to turn freely on the eccentric endportion of a shaft 38 turning in a fixed tubular bearingfmemberlle 38 may be rocked thus bodily moving the roll 31{ toward or from'the roll 36; Preferably the "sur face of the roll '36' is covered with-rubber or other friction material.

Forwardly of the feed rolls 36 and 31 there are arranged rigid guide members 42, 43 and 44 (Fig. 4) which define forwardly divergent inclined guide channels 45 and 45 Forwardly of the guide members 42, 43 and 44 there is arranged'a cutting blade 46 having 'a cutting edge 46*. This blade is mounted 'on a lever "41 pivoted at 48 (Fig. 2) on the frame bar 8. A spring 48 tends to lift the lever 4! and thus to move the cutting blade 46 out of the cutting position. The righthand end of the lever 41 forms a handle 49 (Fig. 2) by means of which the; cutter may be manipulated.

1 Forwardly of the and. 52 define forwardly divergent guide-channels 53and-54 forming extensions of the channels 45 and 45 respective1y. These guide members are rigid and are mounted upon the frame nels 53 and 45 and in a horizontal plane sub-.

stantially midway between the forward ends of these channels there is arranged the winding mandrel 55. This mandrel (Figs. 14 and comprises a part 55 which turns in a fixed tubular bearing 51, supported by the member 5. The mandrelsshaft is provided at its left-hand end with a pinion 58 which meshes .with a gear 59 mounted on a shaft 60 (Fig.2) which turns in bearings in the plate 5 and in the plate 1. As illustrated the ratio of the pinion and gear is twelve to'one. "At its right-hand end this shaft 69 is furnished with a crank 6|, by. means ,of

blade as, fixed guides so,

ii mctrie ti r ac ,qqmmemefitar o he surface 56 and designedfto be i'dispos'edparallel to the surface 56 althoughwith sufficient spacingfbetween; the flat surfaces of the two mandrel members to admit between them the] requisite number of sheets of paper and foil. The part 59 of the mandre1 is fixed to or integral with a spindle '50 turning freely in a bearing in the c. upper part of the memberjl, the" spindle being furnishedat. its right-hand end with. 'a knurled disk for wheel 6| bymeans of which it may be manipulatedthe spindletfl 'being free to slide in its bearing aswell asto turntherein.

The axial movement of the spindle 59* is sum cient to permit separation of the endsof the two remov'al'of a'cornpleted mandrel part'sto permit coil therefrom. v p s 'Above the upper fixedguide member 5| there is arranged a s'winging hook-like retainerfmember 62 pivotally supported at 63*, upon a stub shaft projecting frozn partlj; while a similar hooked retainer e4ff isjpiviot dat .65 upon a stub shaft, projecting frompartj at a point below the lower guide" member 1 5 l L Since the retainer member 64 is somewhat iiiaccessible, it is. pre--,

ferred to provide it withanj actuating handle 65 (Figs. 1 and 2). I p A'shaft B6 (Fig.2) is mounted to turn and to slide in a suitable bearing, carried by the bar 6 of the frame, the shaft 66 having a manipulating disk 6'! atone end While its opposite end is hook-shaped, having a portion 68 which is spaced from but parallel ,to the main part. v66 of the shaft.

Mounted on the fram e member5 is a reservoir.

69 for the reception, of adhesive, the reservoir having a horizontal delivery portion Ill/located conveniently for removal of adhesivev by the operator for application to the outer wrapper of paper, and s on a post carried .by, part -5 is; a counter mechanism 13 of conventional type having an actuating lever 12.

. The operation of th'e'machine jissu bstanti ally as follows;

If it be assumed that the r eels"";|4 are supplied: with paper and foil and .thatithe. machine ..is't'o1 be sta'rtedfofthe first time, the strips of paper which the shaft may be turned. Preferably-the into the depression "in -the disk 62 causing. a

slight'noise and resistance to turning and by counting the number-of clicks the operator'may determine how many turns or half turns the shaft has been rotated and thus may determine the number of turns of the coil being wound.

- The right-hand end portion 56 w (Fig. 14) of the mandrel ,is unsupported and is slabbed off to provide thesu'ostantially flat diametrical surface 56 of Fig. 15. At the inner end of this flat surface the mandrel carries a fixed collar 51 and the flattening of the mandrel provides a sub-- stantially semi-circular pocket 58* within'the collar. r

,The mandrel comprises a secondmember 59 (Fig. 14) which is likewise slabbed off to provide and foil are first drawn ofi'from the reels and, passed beneath guide rolls on the stub shafts l 8, I9, 20 and ZIa'nd 'then' over the guides 22, 23,114.

and 25, respectively. The operator then manipu lates the handle 4i so as to' separate the feed rolls 33 and 3'! andpulls the several strips of materia'l between the rolls and to a point forwardly of the plane of the blade 46. The operator then moves the handle 4| forwardlyto close the rolls,

and foil will befed forwardly, theoperator guidmg them'during this threading up operation into the guide passages 53 and 54. The strips are fed.

forward sufliciently to provide ends which'inay be grasped at the ,forward ends ofthejpas sages 53 and 54. The operator'thenjseizes theffo' il.

wardly projectingends of the paper stripsPfand P 4 and the foil, F" andfturns them down Fig. $3) 7:

into contact'with the'fiat surface"ss eftne man l f fiat surf aces f the] mandrel mem-g mandre ar 5.9? ati inth qeke 58 1h d ll-" l Th in tmem ers. 62" en li fli re: new in t d; t their t n pera v osi i he handle 4 l islfmoved' m; the rearward position; in; die t d 11 b ken lines, in E'ie-v 3: th r by en-l istrated mi ten; the iertfrnan ienebr arat irigfthe feed rollslil fi g 8); a d trge operatortime the cr nk 1* hus re tin asm ndr l n a ounterclockwise directi n. This results in .5 .105 n 1: rine. his; a erat o :v 9 ator counts the clic ksgmade by the detents fifl set-trimmed number, of tirnes requisite to make acoil of the desired number, of turinsgthe operator stops the Winding operation and pushes the ban: i 94! q w rd yto,asubstan al y v tiea pos ertl9 i F g 2 l st i fi titet r f au e e upper roll to bearfriotilonally upon, the upper s't inP' o naperbu wit, tj u cien p ssu to causetheother strip to feed. The: operator ewt' l s e he an le 4 hus caus n he, upper feed roll to turn and thus feed forward a pqrtion ofthe single paper strip, Pf, thus providing a loose forwardly projecting loop oi this tr n Th Pe ete ne wres es. mem e up ardlygandi'thrusts its f ree end into this loop the peperirkng; 19) and tl ien againVoloses th ro 1ls136; and treats to gripthetseveral strips wrapping the paper and foilaboutl the mandrel 2 e em nt s n ieated. ia am ati al in: Figstion, as shown in Fig.3, In this positio n the rolls V lever 12 of the counter mechanism 13thus p 0;

ceed ne pe ion e-aetuate heq ttet 4t e in he n tia t r a ing-anti em ehi e it be re req s tetq ess the handle, ititherehx to actuate the feed rolls to 'feed the strip forge.

: wardly through the channels 45 anclABe and 53 and 54. so as. t0v present the ends of thestrips f r; a t o to he n rel- At each actuation of the, cutter the operator h he neenm y m ni e e a tua viding; a record oithenurnberof completed coils which are wound. If the coilis of the; nonu e t t e pe at rb nds-- he n i edges of the rnetal foil downwardly and; inwardlyi over the ends of the convolutions afterthe; coil: has beenwithdrawn from the; mandrel, If-=thecoil is of-induotive type-the edges f the foil are not exposed and no further; manipulation; necessary. V

While one desirableaembodiment of'-' the inven 1 tion has been disclosed by way of example it is j V to be understood thatthe invention is. not 1160855, s

sarily limitedto this precise embodiment but is to be regarded as broadly inclusive.of- 'anyv andy all equivalent constructions falling" withinthe scope of the appended: claims. Y

Iclaimz- V 1. Method of winding capacitors which oomprises as steps the drawing fromsuitable sup vi plies and the windingsimultaneous thereto of a:

plurality of strips of paper anda pluralityof strips'of metal foil so that'the convolutions, of metal foil are always separated by convolutions of paper, the continued winding of the strips until the requisite lengths of metal foil have; been wound; temporarily discontinuing the wind "ing, the drawing from the supply, of an addi tibnal e g h i h u ermost. paper st ipv toform an end portion loop the severing: oi all? t ips a o n s between sai loop and ,.the,supn y the winding. of the terminal portions of thei -sew,

eral strips onto the coil, so thatrsaid endportionr.

of the outer paper stripoverlaps.the--ends oLthe several strips of" metal. foil, and adhesively fasm firmly and manipulatesgthe blade so as to out) pperator nowfwithdraws thefloop -retain ing rn mber.GBJromtheloop of outerpaper strip, sep ratesgthejf eed rolls, and turns thecrankbl ai'p'artj turnfor mere sufiicient to wind the ends 011% the several strips onto" the coil 1 and to wrap the surplus :niat'eria'lof the outerstrip P about.

thefoil so a s lcompletely tocover the ends of the st i t h seine m e e ee h n tening the overlapping end;portion ofithe outer -i paper stripto the underlying:convolutions 2. Method of winding. capacitors which co n -v prises as steps. providing supplies of; papentandg metal foil ribbon, disposing the ends of two metal;

foil ribbon and at; least two;paperribbons;in

' registrywith one paper stripinterposed;between two; metal; foil ribbons,- advancing the end ofyone: paper stripandone foil ribbon along; a; pred m 55 termined path while advancing the;eh dqf: the;- other paper trip and theother -metal,foil ribbon foliln Since the distances from the tangent points (where the" two strips of'foil'contact the wound coil) to. therespective cutting points are v substan 'l ly equal due to the. position or the guideways' 9', with the advar'icing endstof the two-pairs ope.

' ndl.54,thel endsof the two strips oi foil a re.

r ew.

'The. ope at I applies adhesive; from the, i st e 0 to the n r riee ft he d ti i "t 'paperistrip Efand sticlss this enddown V 'tosthe ndeiflyin paper, Sher then withdraws v th In rnber 59 of thernandrel by; manipu;

7 n. a de en t o hel utevrmo enerst p e e znv n. n por on loo et en. oil

is resuming thewinding to bring the terminal 'p,

along a divergent path, overlappingtheend:1391?; v tions oi one foil and paper strip-and the; end; portions of the; other foil and" paper strip: but:

positely directed, rotating; said overlappedaendeportions'about an axis-intervening-betweenthe overlapped ends and extendingtransversely oi the lengths of the ribbonthereby-to form a-woundj; coil in which the convolutionsof foil are separated by convolutionsoi paper; temporarily stopping the winding; drawing from the supply su ply I cut in r nsv rsely r u h, s hersey e trip t i ts b tw ena e lobe and. e un,

pns 7 2.23 the-( 1 1i onto; the oi andlappl g Y e;

portion of the outer paper strip before completing the winding f the latter.

ERNST A. NORDBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,886,063 Sprague Nov. 1, 1932 1,940,847 Danziger Dec. 26, 1933 1,608,179 Marchand Nov. 23, 1926 1,931,009 Phelps et a1 Oct. 17, 1933 1,346,700 Carlsen July 13, 1920 Number Number German Aug. 3, 1937 

